M177 vs M178 — What's the Difference Between AMG's 4.0L Twin-Turbo V8 Engines?
Mercedes-AMG uses two versions of its hand-built 4.0-litre twin-turbo V8: the M177 and the M178. They share the same bore, stroke, and hot-inside-V turbo layout — but they are not the same engine and they are not interchangeable. If you are ordering an engine build, turbo kit, or any internal component, you need to know which one you have. This guide explains the differences.
Quick Comparison
| M177 | M178 | |
|---|---|---|
| Displacement | 3,982 cc (4.0L) | 3,982 cc (4.0L) |
| Configuration | 90° V8, DOHC, 32-valve | 90° V8, DOHC, 32-valve |
| Turbo layout | Hot-inside-V | Hot-inside-V |
| Oil system | Wet sump | Dry sump |
| Block casting | M177-specific | M178-specific |
| Oil pan | Conventional sump pan | Flat pan + external oil tank |
| Accessory drive | M177-specific routing | M178-specific routing |
| Vehicles | C63 (W205), E63 (W213), GT63, GLC63, GLE63, GLS63, S63 | AMG GT, GTS, GTR, GT R Pro, GT Black Series |
| Application | Sedans, SUVs, four-door coupes | Two-door sports car only |
The Key Difference: Oil System
The fundamental difference between the M177 and M178 is the oiling system.
The M177 uses a conventional wet sump — the oil sits in a pan bolted to the bottom of the block, and a single oil pump draws from the pan. This is the standard layout used in most production engines. It works perfectly in sedans, SUVs, and four-door applications where sustained high-G cornering is not the primary design constraint.
The M178 uses a dry sump — the oil is stored in a separate external tank, and multiple scavenge pumps pull oil out of the shallow pan and return it to the tank. A pressure pump then feeds oil from the tank to the engine. This system ensures consistent oil pressure under extreme lateral acceleration — critical for a low-slung sports car doing sustained track work. It also allows a lower engine mounting position, which lowers the car's centre of gravity.
Block Casting Differences
Because of the different oil systems, the M177 and M178 use different block castings. The oil passages, pan mating surfaces, and accessory mounting points are not the same. You cannot bolt a wet-sump oil pan onto an M178 block, and you cannot retrofit a dry-sump system onto an M177 block without significant custom fabrication.
This is why it is critical to order the correct engine build for your chassis. An M177 crate engine will not fit an AMG GT, and an M178 crate engine will not fit a C63.
Which Vehicles Use Each Engine?
M177 (Wet Sump)
- Mercedes-AMG C63 / C63 S (W205 / C205 / S205 / A205)
- Mercedes-AMG E63 / E63 S (W213 / S213)
- Mercedes-AMG GT 63 / GT 63 S (X290 four-door)
- Mercedes-AMG GLC63 / GLC63 S (X253 / C253)
- Mercedes-AMG GLE63 / GLE63 S (W167)
- Mercedes-AMG GLS63 (X167)
- Mercedes-AMG S63 (W222 / W223)
M178 (Dry Sump)
- Mercedes-AMG GT (C190 / R190)
- Mercedes-AMG GT S
- Mercedes-AMG GT R / GT R Pro
- Mercedes-AMG GT C
- Mercedes-AMG GT Black Series
Simple rule: If your car is a two-door AMG GT, you have the M178. Everything else with AMG's 4.0L V8 uses the M177.
How to Identify Your Engine
The easiest method is to check the vehicle — if it is a two-door AMG GT, it is the M178. All other AMG models with the 4.0L twin-turbo V8 use the M177. You can also find the engine code on the dataplate or in the vehicle documentation.
If you are unsure, contact us at sales@ypgmotorsport.com with your VIN and we will confirm which engine you have.
Engine Builds for Both
YPG Motorsport builds both M177 and M178 engines — short blocks, ported heads, and complete crate engines — with forged internals capable of 1,500 HP+.
| Build | M177 | M178 |
|---|---|---|
| Crate Engine | M177 Crate Engine | M178 Crate Engine |
| Short Block | M177 Short Block | M178 Short Block |
| Ported Heads | M177 Ported Heads | M178 Ported Heads |
Not sure which build level you need? Read: Short Block vs Long Block vs Crate Engine — What's the Difference?
Frequently Asked Questions
Can I swap an M177 into an AMG GT?
Not without major custom work. The oil system, block casting, and accessory layout are different. Order the correct engine for your chassis.
Do M177 and M178 share the same cylinder heads?
No. The head castings differ between the two engines. Our ported heads are built specifically for each engine code.
Which engine makes more power stock?
It depends on the variant. The AMG GT Black Series (M178) makes 720 HP stock — the highest factory output. The E63 S (M177) makes 603 HP. Both respond extremely well to ECU tuning and turbo upgrades.
Are the turbochargers interchangeable?
In some cases, but fitment and plumbing differ due to the oil system and chassis packaging. Contact us for turbo upgrade options specific to your engine.
How do I confirm which engine I have?
Two-door AMG GT = M178. All other AMG 4.0L V8 models = M177. Or send us your VIN for confirmation.